Relevant prior art is disclosed in U.S. Pat. No. 3,549,861 showing a self-heating insulated bottle. Also of interest is U.S. Pat. No. 3,129,318, a thermally insulated coffee percolator, U.S. Pat. No. 3,596,692 for a blender coupling and U.S. Pat. No. 3,175,594 for a blender with special cooling of the motor.
Blender containers of the prior art make no provisions for maintenance of the temperature of the contents. The container walls are generally of a single layer of plastic or metal. The agitation of the contents further enhances the heat transfer through the container walls. When cold contents ae blended, the outer surfaces of the container may be cooled below the dew point, causing condensation of moisture on the outer walls. Cold drinks in containers of the prior art do not remain cold for long.